tube sound fuzz...tube sound preamp?

[Muldoer]

Has anyone ever attempted this? I'm trying to make myself an amp, which I want to do so as simply and cheaply as possible. I was looking at the 100W guitar amp project at ESP and wanted to only build his power amp, giving me the ability to switch preamps for different tonal possibilities.

So, in essence, my question: Is it possible to make a tube sound preamp, just as we can make a tube sound fuzz?

[brett]

Try "Odie" at runoffgroove.com - it's a tube-sounding pedal that goes from clean to overdriven tube at the turn of a knob.  It does this by using 2 jfets as the amplifiers.  They work in quite a similar way to tubes (ie transconductance, etc), so it's no surprise that "Odie" has a very tube-like feel to it.
Good luck.

PS I think that the Odie will turn out up to about 5V p-p, which should be ample to drive your power amp.

[gez]

So, in essence, my question: Is it possible to make a tube sound preamp, just as we can make a tube sound fuzz?

You mean a CMOS 4049 type circuit?  Sure, why not?!

[bobbletrox]

are there any tube circuits that run on batteries (bipolar, maybe?) -or are they all mains power?

[spongebob]

Has anyone ever attempted this? I'm trying to make myself an amp, which I want to do so as simply and cheaply as possible.

I'm also building my own amp right now, exactly for the same reason (not enough money for tubes :cry:), and so far I have completed the enclosure (1 x 12" speaker) and the power amp section. The power amp is based on a TDA2050 chip amp, rated at 32 watt. Building a power amp out of discrete components (as on the ESP page) isn't worth it IMHO, and I don't need 100 watt! The few hundred milliwatt out of a LM386 are already loud enough to wake up my neighbours!

One thing you have to keep in mind is that you don't want any distortion/clipping to happen in the output stage (sounds bad), and that chipamp is easily overdriven. Max input level is around 300 mV in my configuration, which can be exceeded easily by your guitar output, so you actually have to cut down the signal level in your preamp.

Odie does indeed sound nice, you could very well use it in the amp's input section. I have yet to decide myself what to use in my amp...

Anyone built the "Tubetype Distortion" as shown on the AMZ project page ? Looks interesting...

[Mark Hammer]

You can take a look at this: http://www.albertkreuzer.com/preamp.htm

Also, take a peek at the various "Minitubes" preamps at www.geofex.com, and the different variations on Jack Orman's minibooster" circuit.

I think you need to start by asking yourself what it is about a "tube" front end that you want most to mimic.  For some people, it is the dirt, and for others its the cleanliness.  For others still it is the headroom and dynamic responsiveness, clean or dirty.  In other words, it is not the "tubeness" of the amp that is at issue but the sorts of qualities associated with a given tube amp design/make.

[Muldoer]

Well the kind of characteristics I am looking for are the warm clean sounds normally associated to tubes. I wouldnt be the type of guy to use amp distortion either, I'd use an external distortion box.

Basically, I'm looking for something to drive a 2X12 to gigging volumes, and not have it sound too "lacking".

[casey]

from what i understand, the tone of a tube amp doesnt come
from the preamp section, but the power tubes.......
just a thought a to keep in mind...

[Muldoer]

I was under the impression that tone always came from the preamp(??)

[puretube]

...both...  (plus the fingers, the cabinet, the spkrs, ..., ..., ...)